Trailer Wiring Problem - Toyota Tundra Forums : Tundra Solutions Forum

ljensen1 · #1 (**permalink**) 10-18-2008, 09:30 AM

Hello,
I'm having a problem with the trailer wiring on my 2006 Sienna. I have two trailers - a utility trailer and a small travel trailer. On each of them, the passenger trailer turn signal and brake light do not work. On the utility trailer, the running lights, also, do not work. I don't think the problem is with trailer wiring or bulbs (completely new lights and wiring harness just put on the travel trailer.

Both trailers used to work fine. All lights on the van itself work fine. I tested the trailer wires coming from the van with a muli-meter: one line of the multi-meter in a connector to a particular wire and the other line connected to the ground pin on the plug. I had the multimeter set up to read 20 volts. The reading jumped all over the place for each wire - from positive to negative and back again. When I tested a standard outlet in the house with the same multimeter it just gave me a straight number that changed very little. Should the reading be like that for the trailer? Am I testing it the wrong way?

Sorry for the length of this post, but there is a little history that might be relavent. I jack-knifed the utility trailer a couple months ago and put a dent in the back passenger side of the van. That caused the side air bag warning on the dash to flash. Haven't had the money to get it fixed, so have just lived with the light. Twice the warning light has gone out and at the same time the van brake lights went. Found the fuse that was blown each time and replaced it. Now the airbag warning light is again out, but everything on the van seems to be working and can't find a blown fuse.

Could the problem with the airbag light mean something is messed up electrionically that could be effecting the trailer lights? Could a blown fuse be effecting the trailer lights even though the van lights are fine?

Thanks for any help!
ljensen

mustang67408 · #2 (**permalink**) 10-18-2008, 04:20 PM

It sounds like the trailer converter box is bad. The voltages should NOT be jumping around, otherwise the lights would flicker.
Pm me your e-mail and I will send you a copy of the installation instructions, It shows the location of the converter box and how to get to it.

mustang67408 · #3 (**permalink**) 10-24-2008, 10:25 AM

E-mail has been sent, let us know what you find.

ljensen1 · #4 (**permalink**) 10-24-2008, 11:11 AM

After looking at what you sent I realized we have an after-market wiring harness. When I look in the back of the van I see we have two wires coming from one taillight, another two wires from the other taillight and a ground. These five wires enter a small black box. Four wires leave the box and head to the trailer. Is this black box our wiring converter?

mustang67408 · #5 (**permalink**) 10-24-2008, 11:24 AM

Yes, that black box should be the trailer wire converter. I recommend the factory trailer wiring converter. PM SENT

ljensen1 · #6 (**permalink**) 10-31-2008, 09:06 AM

We got our new wire harness with converter box in the mail yesterday. My husband installed it and everything works perfectly

Thank you so much for your help!!!

mustang67408 · #7 (**permalink**) 10-31-2008, 09:20 AM

Glad everything works!!!

geneowens · #8 (**permalink**) 11-03-2008, 07:50 AM

Hello,

I also have the 06 - The dealer installed the converter - I'm not sure if it is the recommended one or not. I have recently had trouble with a newly purchased utility/van trailer [Thule]. It appears that the number of lights on the trailer overloads the system and blows the 5 amp fuse at the converter box. I have had to disconnect most of the lights on the trailer except rear brake, running lights and a side marker on each wheel well and the license plate light. The fuse has not blown since but I have not towed for any lenght of time yet??
I am looking into converting the trailer lights to LCDs - this apparently would reduce the amp draw considerably and would allow for adding back perhaps all of the disconnected lights.
Any thoughts/suggestions?
Gene

mustang67408 · #9 (**permalink**) 11-03-2008, 09:15 AM

Quote:

Originally Posted by geneowens

Hello,

I also have the 06 - The dealer installed the converter - I'm not sure if it is the recommended one or not. I have recently had trouble with a newly purchased utility/van trailer [Thule]. It appears that the number of lights on the trailer overloads the system and blows the 5 amp fuse at the converter box. I have had to disconnect most of the lights on the trailer except rear brake, running lights and a side marker on each wheel well and the license plate light. The fuse has not blown since but I have not towed for any lenght of time yet??
I am looking into converting the trailer lights to LCDs - this apparently would reduce the amp draw considerably and would allow for adding back perhaps all of the disconnected lights.
Any thoughts/suggestions?
Gene

Would you be able to take a picture of the converter box? I do not remember a 5 amp fuse at the box of a toyota trailer box converter.
5 amp is no where near enough. I recommend a TOYOTA one.
PM sent

geneowens · #10 (**permalink**) 11-03-2008, 12:50 PM

The box is small black box hidden in compartment on right side of can where the jack is located. There are 4 fuse holders connected to it.

mustang67408 · #11 (**permalink**) 11-03-2008, 12:55 PM

Quote:

Originally Posted by geneowens

The box is small black box hidden in compartment on right side of can where the jack is located. There are 4 fuse holders connected to it.

That does NOT sound like a TOYOTA trailer converter box. The Toyota one is PLUG & PLAY.
Check the instructions I sent you

wells service · #12 (**permalink**) 01-21-2009, 04:59 AM

i presume you put in the correct adapter. take it to u-haul and they will get it right.